Under drill bit



Nov. 30, 1926. l,608,945

R. E. KoRTs Filed Feb. 15, 1926 2 Sheets-Sheet 1 *ZZWMW W Nov. 30 1926.

R. E. KORTS Filed Feb. 15. 19 2 SheetS-Sheet 2 ;W R. E Korfu;

Patented Nov. 30, 1926.

UNlTED STATES RAYMOND E. KORTS, OF OSCAR, OKLAHOMA.

NDER DRILL EIT.

Application filed February 15, 1826.

This invention relates to well drills, and its object is to provide a new and useful construction of such a drill, provided with means for enlarging the hole made by the drill-bit proper, so as to enable a casing` to be lowered into the hole. Such ineans are known as underreainers, and the present in- 'vention, therefore, inay be ternied a coinbined drill-bit and underreainer, although C the iniproven'ients relate to the underreaniing means only, which ina'y be used independently of the drill proper.

Such a combined tool is cover-ed by iny Patent No. 1,012,5(5?, issued December 19, 1911, and the present invention consists in ilnproveinents thereover.

The essential features of a tool of this kind are that the underreainer cutter, or cutters, shall be retractable to perniit the tool to be withdrawn froin the hole through the cas ing, and that it, or they, shall be positively and solidily held in the body of the tool when in operative reaining position.

According to the present`iin1nroveinents, the cutters, which have grooves in their top rear faces engaging pins which act as fulcrum pins, are inoved into and held in their extended outward positions by blocks slidable on nclined surfaces in the cutter-re- 30 ceiving slot of the body and having a wedging engagement with the lower rear ends of the cutters, the effect being to hold the cutters wedged between said blocks and the top of said slot, thus relieving` said pins of thrust. Furthermore, in the practical operation of this tool, the space in said slot behind the cutters becomes filled with liquid mud under pressure when the tool is lowered into the well, and since egress for this inud is substantially closed when the cutters are in outward opcrative position, it serves to prevent thein from receding or moving inward into the shank or body, thus inaintaiir ing the diaineter of the hole at full The mud can, however, be slowly expelled by sustained pressure forcing the cutters inwardly, so that the tool can be retracted from the well.

In niy prior patent aforesaid, I showed a tool provided with only one undei'reamer, while the new tool has two such cutters, but this is not in itself new.

The improvements are illustrated in the accompanying drawing, in which Figure 1 is a side elevation of the tool;

Snral Ne. 88,271.

Figure 2 is a central Vertical section of the saine;

Figure 3 is a horizontal section on line 3-3 of Figure 1;

Figure i is a central Vertical section with the underreainers and their appurtenant parts renioved;

Figure 5 is a perspective view of one of the underreanier bits;

Figure 6 is a perspective view of the spring' for expanding said bits, and

Figure T is a perspective view of one of the blocls which close the spaces below the ends of said hits and the body or stock of the tool.

The body or shank 1 of the drill, conipi'ising the bit 2, at its lower end, and the taper threaded stem 3, at its top, has a slot 4 passing entirely .through its central portion. Both walls of said slot arc provided, adjacent their outer edges, with i'aised ribs or fianpy'es 5, the inner edges of which constitute downwardly inclined shoulders 6 to retain the underreanier cutters, as will be explained below. Three pins 'T are passed through the body near the top wall of the slot L1 and between the Shoulders G. The bottoin wall 8 of the slot is inclined (lownwardly fron'i each side at a very obtuse angle, and the top wall is likewise inclined downwardly froin each side to a central line.

The underreamer cutters 15 have the shape best shown in Figure the sides of the body 10 are recessed to leave the Vertical ribs 11, constituting` shoulders 12 to engage the Shoulders 6 of the drill body, and to leave horizontal shoulders 13, which contact with the lower cnds 14: of the ribs 5, when the reamer cutters are in operative position, as shown in Figure 2. The top surface 16 of each cutter is beveled at 1'2', to perinit the cutter to rock in the drill body with its top in Contact with the top wall 9 of the slot and the Cutting,` end 18 of the bit has a notch 19 in its rear side, to lit on a wedge block 20, loosely inounted in said slot on the bottom wall 8. There is, of course, a block 20 on each side, and they are pressed outwardly by a V-shaped flat spring 21, hung on the central pin 7 so that its bent cnds 22 abnt the rear sides of said blocks, which inay be grooved to receive said ends. The rear side of each reainer cutter is provided with a senii-circular groove 23, to fit one of the outer pins 7, which thus constitute fulcruins on which the rearner cutters roc-k. The outer faces of the cutters are be'veled at 24,, so

that the cutters will be forced inward-ly byl the contact of said faces with the lower end of the casing, when the tool is to be withdi'awn from the well.

The operation will be clear from the above description and the drawing. VVhen the cutters are expanded by the spring into operative position, they are held solidly between the. blocks 20; and the top wall of the slot 4, the pins 7 taking none of the impact force, and the 'slot is closedagainst the egress of mud by the bloclrs, which wedge themselves between the bottom wall of the slot and the top walls of the notches in the cutters, under the influence of the spring., while sli-'ghtly lifting the cutters. ft will be noted that the slot 4 is identical on each side, azs are both sides of the cutters and the bloclrs 20, so that said. icutters and blochs are interchangeable. The cutters are readily removable from and i-nsertible in the slot, it being' only necessary to push in the bloclrs 20 andV drive out the pins 7, when the cutters can be pull-ed out past the horizontalf Shoulders at the lower endsv of the ribs or flanges.

The structure d'escrizbed fulfills all' the requirements ofv a tool of this kind, since it droesnot break or get out of order.

Having thus descri'bed my invention, What I claiin is:

1. An under-drill bit having a cutlterreceiving slot therethrough, the bottom wall of which is inclined downwardly to the center from each side, a pair of' underreamer cutters mounted: in said slot, means. to limit the o utward' movement of said cutters, and

spring-actuated means slidable on said bottom wall, tending to force. the cutters outwardly, to Wedge them tightlfy up against' the top Wall of said slot and to close the space between the ends of the cutters and said' bottom Wall.

'2.v drill bit having a slot extending through the shank thereof, a pair of underreamer cuttersinounted to swing in said slot, one on each side, a pair of blocks slidable in said slot, each engaging the; lower end of-v one of saidV cutters, and a spring to slide said bloclis apart, said' blocls substantially elo-sing the space. behind' and: between said cut-ters.

3. A drill' bit having a slot extending through the shank thereot, the bottoin of said slot being inclined downwardly.. from each side to the center of the shanl: and. the side walls: of said slot being provided Wit-h stop Shoulders, av pair of underreainer cutters roclringly lnounted in said slot and having` ribs to engage said Shoulders to limit their outward movement, a pairof Wed-ge bloclszs, one for each cutter, slidable on the said nelined bottom of: the slot and engaging a, correspondingly shap ,d notch in the rear lower end of the respective cutter, and a spring. tending to force said bhocks outwardly, whereby,when the cutters are operative position, they are firmly wedged be.-

tween said blocks and the; top of said slotand the. space between thel cuttersis substanti'al'ly closed against egress of' liquid innd.

In'testiunon'y whereof I have. hereuntol set my hand. i

RAYMQND E. Komis.

till 

